diff --git a/packages/opencode/src/session/code-mode.ts b/packages/opencode/src/session/code-mode.ts
index 14c242f95c..a96f451230 100644
--- a/packages/opencode/src/session/code-mode.ts
+++ b/packages/opencode/src/session/code-mode.ts
@@ -156,19 +156,26 @@ const returnType = (outputSchema: JSONSchema7 | undefined) =>
 const signatureFor = (entry: CatalogEntry) =>
   `tools${access(entry.server)}${access(entry.local)}(input: ${inputType(entry.tool)}): ${returnType(entry.outputSchema)}`
 
+/** The compact, directly-callable signature for the inline preview: the call path
+ *  plus its input type, but without the (uniform) `Promise<{ result, attachments? }>`
+ *  return — that full typed form is reserved for `tools.$rune.describe`. */
+const previewSignature = (entry: CatalogEntry) =>
+  `tools${access(entry.server)}${access(entry.local)}(input: ${inputType(entry.tool)})`
+
 /**
- * Character budget for the inline tool preview in the tool description. All
- * namespaces are always listed; individual tools are previewed (cheapest first,
- * server by server) until this many characters of preview lines are used, after
- * which the remaining namespaces show counts only. This front-loads a useful slice
- * of the catalog — cutting discovery round-trips — without dumping every tool.
+ * Character budget for the inline signature preview in the tool description. All
+ * namespaces are always listed; per-tool call signatures are previewed (cheapest
+ * first, server by server) until this many characters are used, after which the
+ * remaining namespaces show counts only. This front-loads a directly-callable slice
+ * of the catalog — cutting discovery round-trips — without dumping every signature.
  */
 const PREVIEW_BUDGET = 2000
 
 /**
  * The execute tool description: the calling convention, the discovery API, and the
- * list of namespaces. A budgeted preview of individual tools is inlined; the full
- * per-tool signatures are still fetched on demand with `tools.$rune.describe`.
+ * list of namespaces. A budgeted preview of per-tool call signatures is inlined; the
+ * full typed signature + schemas are fetched on demand with `tools.$rune.describe`,
+ * and any tool not previewed must be found via `tools.$rune.search` first.
  */
 export function describe(groups: Map<string, CatalogEntry[]>): string {
   const lines = [
@@ -193,14 +200,19 @@ export function describe(groups: Map<string, CatalogEntry[]>): string {
     lines.push("", "No MCP servers are currently connected.")
     return lines.join("\n")
   }
-  lines.push("", "Available namespaces (use tools.$rune.search / tools.$rune.describe to explore tools not shown):")
+  lines.push(
+    "",
+    "Every connected server is listed below with its tool count. A budgeted sample of tool",
+    "signatures is shown inline; any tool not shown must be found with `tools.$rune.search` /",
+    "`tools.$rune.describe` before you call it.",
+  )
   let used = 0
   let previewing = true
   for (const [server, entries] of [...groups].sort(([a], [b]) => a.localeCompare(b))) {
     lines.push(`- ${server} (${entries.length} tool${entries.length === 1 ? "" : "s"})`)
     if (!previewing) continue
     for (const entry of entries) {
-      const line = `  - ${entry.path}${entry.description ? ` — ${brief(entry.description, 80)}` : ""}`
+      const line = `  - ${previewSignature(entry)}`
       if (used + line.length > PREVIEW_BUDGET) {
         previewing = false
         break
diff --git a/packages/opencode/test/session/code-mode.test.ts b/packages/opencode/test/session/code-mode.test.ts
index 38c7ba1687..0c4ad4d815 100644
--- a/packages/opencode/test/session/code-mode.test.ts
+++ b/packages/opencode/test/session/code-mode.test.ts
@@ -65,10 +65,14 @@ describe("code mode execute", () => {
     await expect(Effect.runPromise(decode({}))).rejects.toThrow()
   })
 
-  test("lists all namespaces, previews tools within budget, and documents discovery", () => {
+  test("lists all namespaces, previews tool signatures within budget, and documents discovery", () => {
     const groups = groupByServer(
       {
-        github_create_issue: mcpTool("create_issue", () => ""),
+        github_create_issue: mcpTool("create_issue", () => "", {
+          type: "object",
+          properties: { title: { type: "string" }, body: { type: "string" } },
+          required: ["title"],
+        }),
         github_list_issues: mcpTool("list_issues", () => ""),
         linear_search: mcpTool("search", () => ""),
       },
@@ -78,21 +82,23 @@ describe("code mode execute", () => {
 
     expect(description).toContain("tools.$rune.search(query")
     expect(description).toContain("tools.$rune.describe(path)")
+    // Every namespace is always listed, with counts.
     expect(description).toContain("- github (2 tools)")
     expect(description).toContain("- linear (1 tool)")
-    // Small catalog: individual tools are previewed inline as `<server>.<tool>`.
-    expect(description).toContain("github.create_issue")
-    expect(description).toContain("linear.search")
-    // ...but never full signatures (those come from tools.$rune.describe).
+    // Tools are previewed inline as compact, directly-callable input signatures.
+    expect(description).toContain("tools.github.create_issue(input: { title: string; body?: string })")
+    expect(description).toContain("tools.linear.search(input: object)")
+    // ...but not the full Promise return — that comes from tools.$rune.describe.
     expect(description).not.toContain("): Promise<")
   })
 
   test("falls back to namespaces-only when the catalog exceeds the preview budget", () => {
     const tools: Record<string, AITool> = {}
-    const longDesc = "performs a meaningful operation against the service with several options"
     for (let i = 0; i < 60; i++) {
-      tools[`alpha_op_${i}`] = mcpTool(`op_${i}`, () => "", { type: "object", properties: {} })
-      ;(tools[`alpha_op_${i}`] as any).description = longDesc
+      tools[`alpha_op_${i}`] = mcpTool(`op_${i}`, () => "", {
+        type: "object",
+        properties: { value: { type: "string" }, count: { type: "number" } },
+      })
     }
     tools["zeta_only_tool"] = mcpTool("only_tool", () => "")
     const groups = groupByServer(tools, ["alpha", "zeta"])
@@ -101,10 +107,10 @@ describe("code mode execute", () => {
     // Every namespace is always present, with counts.
     expect(description).toContain("- alpha (60 tools)")
     expect(description).toContain("- zeta (1 tool)")
-    // The preview is budget-capped, so the later namespace's tools are not all inlined.
-    expect(description).not.toContain("zeta.only_tool")
-    // Some early tools are still previewed.
-    expect(description).toContain("alpha.op_0")
+    // The preview is budget-capped, so the later namespace's signatures are not all inlined.
+    expect(description).not.toContain("tools.zeta.only_tool(")
+    // Some early signatures are still previewed.
+    expect(description).toContain("tools.alpha.op_0(")
   })
 
   test("tools.$rune.search and tools.$rune.describe expose the catalog on demand", async () => {